Bicycling is recognized by the avid mountain and road cyclists riding on hilly or mountainous terrain or by the average or “Sunday” rider as a particularly effective type of aerobic exercise. Also, bicycling provides a low impact type of exercise which is especially easy on the knees and feet. As a result, stationary exercise bicycles facilitating this type of exercise are popular for both home and health club use.
With respect to operation of exercise bicycles, research has shown that the optimum position seating for bicycling is for the seat to be at a height that allows for approximately 15 degrees of leg bend when the rider's foot is at the lowest pedal position and for the seat post to be positioned rearwardly of the pedal crank and along a line passing through the pedal crank at an angle of approximately 71 degrees from the horizontal. Thus, the seat positioning requirements for optimum performance can vary greatly from rider to rider.
It has also been found that even slight movements of seat position will work either different muscles and/or different parts of the muscles. Typical seat position mechanisms provide only widely spaced adjustments which can limit the user's ability to comfortably work different muscles.
In view of these issues and others, it is clear that a highly adjustable seat positioning system is needed, one that is easily controlled. The most common form of seat height adjustment involves using a pin, usually secured to the exercise bikes frame and often spring loaded, that is inserted into one of a number of holes in the seat post in order to position the seat. However, this arrangement has a number of disadvantages including the necessity of dismounting the bike to pull the pin out and because of the spacing of the holes on the post, the seat can only be positioned in increments that are on the order of one inch. One approach to solving this problem has been implemented on an exercise bicycle manufacture by Cybex Intl. of Medway, Massachusetts. In this product, the seat post is configured with openings having a flap portion bent inwardly on the lower edge each of the openings which permit the user to pull the seat up to a new position without pulling the pin out. This arrangement provides a ratchet effect in that the flaps will guide the pin out of the openings while the seat post is moving up. However, it is still necessary for a user to manually pull the pin out to lower the seat. Also, the shape of the openings results in vertical seating increments of at least one inch. One approach to solving these problems is described in U.S. Pat. No. 6,913,560 where a rack is secured to the seat post and a latch mechanism including a release handle permits the seat to be lowered.
The desirability of fore and aft, or horizontal, adjustability has also been recognized. A number of “spin” type exercise bicycles produced by companies such as LeMond and Star Track employ mechanisms that allow the seat to be moved fore and aft. Typically, these mechanisms use screw type clamps to lock the seat in place. One example uses an assembly that mates with the seat post and slides fore and aft relative to a top plate on the seat post. A screw, having a knob attached and that mates with threads on the seat, is used to clamp the seat in position relative to the seat post. These types of mechanism have a number of disadvantages including being awkward for a user to use.
Seat adjustment capability is also desirable in recumbent type exercise bicycles. Typically, adjustment mechanisms on these types of machines permit the seat to move horizontally or at an angle with the horizon to accommodate users of different heights. As an example, Life Fitness, a division of Brunswick Corporation provides a recumbent exercise machine having a seat mounted for movement along a track where a handle attached to a spring loaded pin on one side of the seat is used in combination with a rack bolted to the side of the track to hold the seat in place.